Transition metal catalysis remains a key enabling technology for the production of fuel. Petroleum upgrading processes, particularly hydrotreatment, involve the reductive cleavage of polar bonds such as carbon-sulfur and carbon-nitrogen bonds, processes commonly referred to as hydrodesulfurization (HDS) and hydrodenitrogenation (HDN), respectively. The efficient and complete removal of sulfur and nitrogen atoms is desired for the production of environmentally safe fuel because the combustion of sulfur- and nitrogen-containing components of petroleum results in increased emission of gaseous pollutants (SOx and NOx) to the atmosphere.
Current hydrotreatment catalyst technologies are energy intensive (R. R. Chianelli et al. Catalysis Today 147 (2009) 275-286). This is due in part to the reaction conditions required for the metal catalysts to function. For example, cobalt- and nickel-promoted catalysts, such as CoMoS2 and NiWS2, generally function at high temperatures and high hydrogen pressures. These heterogeneous catalysts, in some cases, function at temperatures ranging from 300-650° C. and hydrogen pressures ranging from 90 to 120 atm or higher. The range of process conditions varies with catalyst formulation. These high temperature and high pressure conditions add to the refining costs of petroleum and crude oil. Hence, there remains a demand for cost-effective catalyst technologies for petroleum upgrading.